You forge a covenant with your ally. Anyone foolish enough to attack that ally will suffer your wrath.

Daily   ✦     Divine
Minor Action      Close burst 10

Target: You or one ally in the burst

Effect: All of the target's marks end. Until the end of the encounter or until the target marks a creature, if a creature attacks the target, you and your allies gain a +4 power bonus to attack rolls against that creature until the end of your next turn.

Published in Player's Handbook 2, page(s) 111.